Twenty fire engines and 120 firefighters and officers have been called to a blaze on the roof of a hotel in Knightsbridge, central London, the London Fire Brigade said on Wednesday.
The cause of the blaze was not yet known, it added.
A Reuters reporter said smoke was visible coming from the five-star Mandarin Oriental hotel.
Police said the hotel was being evacuated and it was not yet known whether there had been any injuries.
(Reporting by Andrew MacAskill; editing by Stephen Addison)
A huge fire has engulfed exclusive central London hotel the Mandarin Oriental, sending large plumes of smoke billowing above the the capital.
The London Fire Brigade (LFB) said it had sent 20 fire engines and 120 firefighters to the blaze in Knightsbridge